Ready To Install To Make A Reliable, Clean Running Piston Rifle

Complete Base upper receiver assembly comes ready to install on mil-spec lower receiver to produce a reliable, positive-cycling gas piston gun. Adams Arms’ proven piston system doesn’t vent hot gases and burned powder into the bolt carrier and receiver, so the gun runs cooler, with less fouling and wear on the action, and easier maintenance. Short-stroke piston shaft eliminates concussive gas expansion in the upper receiver for less violent cycling, smoother feeding, and reduced felt recoil. The receiver is forged from 6061 T6 aluminum and features M4 feed ramp cuts and a 13-slot Picatinny-cut flattop rail. The adjustable gas block allows three levels of gas release: normal fire, firing with a suppressor attached, or a single round fired without cycling. Picatinny rail on top of gas block accepts a variety of clamp-on tactical sights. All models have melonite-lined barrels chambered for 5.56mm NATO, with an A2 flash hider and a black Melonite® finish for superb wear resistance and up to 60% more corrosion resistance than traditional phosphate coating. Carbine - 16" barrel and M4-style carbine handguard. Mid-length – 16" barrel with a mid-length gas system that taps gas from farther up the barrel than a standard carbine-length gun for extra-smooth cycling and extraction. M4-style handguard.